Digesting apparatus



(No Model.) 3 Sheets-Sheet 1.

- A. SYELKIRK.

DIGBSTING APPARATUS.

Patented Nov, 15, 1892.

Iii?

PSOTDLFTNOY, WASHINGTON, o. c.

(No Model.) 3 Sheets-Sheet 2.

A. SELKIRK. DIGESTING' APPARATUS.

Patented Nov. 15,1892.

THE NQRR S PETERS 00.. PHmouTHQ. WASNINUTON, u c

3 Sheets -Sheet 3.

(No Model.)

A. SELKIRK. DIGESTING APPARATUS.

No. 486,130. Patented Nov. 15, 1892.

UNITED STATES PATENT I OFFicE'Q ALEXANDER SELKIRK, OF. ALBANY, ASSIGNOR, BY MESNE ASSIGNMENTS,- TO ROBERT VHITEHILL AND DANIEL S. WARINGQOF NEWBURG, NEWV YORK.

DIGESTING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 486,130, dated November 15, 1892.

Application filed March 5, 1889.

to fiber or paper-stock by means of a highly-- heated chemical cooking-liquor, and especially to the apparatus described and claimed in 'ap-,

plication Serial N 0. 312,749, filed May 31, 1889, for carrying out the process covered in application Serial No. 282,012, filed August4,1888.

The invention consists in the construction and combinations of parts hereinafter particularly described, and specifically set forth in the claims.

In the accompanying drawings, Figure 1 is a sectional view of the digesting apparatus. Fig. 2 is a sectional view of the lower portion of the digesting-vessel on an enlarged scale. Fig. 3 is a sectional view on an enlarged scale, taken at line 3 in Fig. 1, with one part of the reinforcing ring-piece broken away. Fig. 4 is a sectional view taken at line A in Fig. 1, with the perforated bottom broken away for exposing parts below.

The same letters of reference refer to like parts throughout the several views.

In the drawings is shown in Fig. l a digesting apparatus of a similar construction to those described in the applications hereinafter referred to and is provided with the necessary pump and system of pipes to induce the dual circulation therein described and with liquor-heating devices covered in applications Serial Nos. 3l2,750 and 312,752, filed May 31, 1889. These devices form no part of the invention sought to be covered in this case, and other constructions and arrangements of devices may be substituted for them without changingtheoperation of the devices herein claimed, and they are shown and will be briefly described solely for the purpose of affording a clear understanding of the construction and operation of the specific improvements hereinafter claimed.

A represents the digesting -vesse1, constructed of iron or steel in the usual form and Serial No. 301,377. (No model.)

provided at each end with the ordinary covered manholes or openings, thatpermit access to be had to the interior. At the ends of the digesting-vessel Aare located the liquor-heaters G and Q, of any suitable construction, but preferably that shown, which is a form fully described in application hereinbefore referred to. These heaters have suitable pipe communicationssuch as pipes M, M M M and M as shown in Fig. 1with the main steam-supply pipe M, and are also provided with means for directing through them currents of cooking-liquor.

E is a pump having its discharge-opening connected by abranch pipe with pipes F and J, which are connected, respectively, to the top and bottom of the digester, and conveys liquor to the heaters above referred to. The pipe F is connected at one end to the inlet of the pump and at the opposite end communicates'with the interior of the digester at or below the middle portion. By this arrangement of the pipes it follows that when the digester is charged with the material to be treated and filled with liquorto a point above the opening of pipe F and the pump is operated the liquor will be continuously drawn from the interior of the digester and forced in two streams, respectively, into the top and bottom of the digester, and thence through the mass of material forming the charge, being heated in its passage by the heaters G and Q; also, the pipe F is connected to pipes F and J by the pipes I and K and to the top of the digester by pipe F, (shown in dotted lines,) and by means of stop-cocks in each of the pipes the direction of the circulation may be variously changed at the will of the operator. Other arrangements of pipes and liq nor-forcing devices may be substituted for those shown, the only essential feature of the construction being that one or more draft-pipes are connected with the digester at or below the middle portion to withdraw the cookingliquor from the interior of the vessel, said liquor to be subsequently forced back into the digester, thereby producing a dual circulation of the liquor. These matters, being fullydescribed in applications before referred to, need no further explanation. I

Inclosed within and concentric with the wall a of the digester and extending for some distance above and below the opening of the pipe F is the perforated plate d. This plate is connected to the wall of the digester at top and bottom by the angle-irons e e, which are riveted or otherwise firmly secured to each, and this plate (1, together with the angle-irons and wall a of the digester, form an annular liquor-chamber D, which has free communication with the interior of the digester through the perforations in plate (I, and from whence the liquor may be drawn by pipe or pipes F. The location of pipe or pipes F not only adds to the efficiency of the apparatus by the production of the circulation of the liquor above described, but it also permits by its connection with the side wall the use of a plate d of greater area than is possible when the draft-pipe is connected with one or the other of the ends of the digester and when the perforated plate forming the liquor chamber is arranged transversely to the digester, and is therefore limited in size by the size of the vessel. The extended area of plate cl is of considerable importance, as it permits the liquor to percolate freely through it without exerting too great pressure at any point, and thereby avoids the clogging and bending of the plate, both of which are accidents of frequent occurrence in the former constructions.

In order that the plate d may be of sufficient area, and yet be prevented from bending and displacement, there should be provided at intervals open supports between the plate and the wall of the digester, which will sustain the said plate in proper place and condition andpermit free communication from all parts of the chamber D to the draft-pipe F. The means I have found convenient for this purpose are shown in Figs. 1 and 3, and consist of a series of rings e, secured by suitable flanges and rivets or equivalent fastenings to the plate (Z and hearing at their edges against the wall of the digester. To permit the necessary circulation of the liquor within the chamber, the outer edges of these rings are formed with notches 6 which should be as deep and as close together as possible without impairing the strength of the rings, so that the communication between the various portions of the chamber D may be as free as possible and reduce the liability of clogging. Although the ring form of bracing device is shown to be used for receiving support from the solid wall of the digester, yet this plate at can be otherwise supported, as by sections of rings or angle-irons secured by rivets or their equivalents to said plate and bearing against the wall of the digester.

As shown, the inner surface of the plate (1 is covered with wire-gauze d, and the use of this covering is preferred, as it enables the perforations in plate at to be of larger size and does not interfere with the passage of the liquor, and yet insures against the passage of any portion of the material forming the charge into the pipe Fan accident which frequently results in an interference with the proper circulation of the liquor.

At the bottom of the digester and above the heater G is secured the usual perforated plate a, which is suitably secured in place and connected with the wall of the digester. The drawings, Figs. 1 and 2, show this plate to be set inclined and having at its lower (lip a perforated step a, which is opposite the blow-off opening B, which opening is provided with a suitable valve B or stop-cock, as is commonly used for controlling the discharge of the cooked product from the digester.

U is a live-steam-supply pipe from the outside of the digester into the chamber below the perforated inclined plate a and has its discharge end a terminating at a short distance rearward of the step (1 This pipe U is provided outside the digester with a suitable valve for control of the passage of steam to be discharged from the pipe through the perforations in the step a and into the product at the blow-off opening B when the stopcock B' is opened and the pressure on the charge of cooked product is forcing the latter downwardly. This steam-pipe will be found to be effective for clearing the product from the inclined plate a as fast as the pressure from above forces theprodnct down on it and prevent the blow-off opening from becoming clogged, as frequently occurs when the charge treated has not been fully reduced.

Having described my invention, what I claim,and desire to secure by Letters Patent, 1s-

1. In a digesting apparatus, the combination, with the digesting-vessel, of a concentric perforated plate of extended area, forming with the wall of the digesting-vessel an annular liquor-chamber, a draft-pipe leading from said liquor-chamber, and means for forcing the liquor withdrawn from said chamber back into the digester, substantially as described, for the purposes set forth.

2. In adigesting apparatus, the combination, with the digesting-vessel, of a concentric perforated plate forming with the wall of the digesting-vessel an annular liquor-chamber, open supports arranged at intervals between the wall of the vessel and the perforated plate and sustaining the latter in place, a draft-pipe leading from said liquor-chamber, and means for forcing the liquor withdrawn from said chamber back into the digesting-vessel, substantially as described, for the purpose set forth.

3. In a digesting-vessel, the combination, with the wall of the digesting-vessel, of aconcentric perforated plate (I. forming with said wall of said vessel an annular chamber D, the rings e, provided with notches or openings 6 a draft-pipe, a pump, and pipes discharging into the respective opposite ends of thedigesting-vessel, substantially as and for the purposes set forth.

4. In a digesting apparatus, the combina cameo 3 tion, with the concentric internal perforated plate a, set inclined and having at its lowest plate d, forming with the wall of the digestdip the perforated step a, neighboring the ing-vessel the annular liquor-chamber D, of blow-0E opening, and the live-steam plpe U, I 5 the wire-gauze covering 01', a draft-pipe leadhaving a valve under control of the operator 5 ing from said liquor-chamber, and means for and its discharge end directed to the sa1d step forcing the liquor withdrawn from said chama, substantially as and for the purposes set ber back into the digesting-vessel, substanforth. tially as described, for the purpose set forth. ALEXANDER SELKIRK 5. In a digestlng apparatus, the comblna- 10 tion, with the digestingvessel having the Witnesses:

blow-off opening provided with a stop-cock PETER HOGAN, controlled by an operator, of the perforated CHARLES SELKIRK. 

